Shock absorber



May 19, 1931. A. F. BLANCHARD 1,806,038;

. SHOCK ABSORBER Fi led May 11, 1929 2 Sheets-Sheet 1' mwmlm mun , INVENTOR. ADA A I BLANCH/7R0,

- A TTORNE Y.

Patented May 19, 1931 UNITED STATES PAT NT- OFFICE.

AIDNA F. BLAATCHARD, OF NEW YORK, N. Y., ASSIGNOR T GUY G. S EATON, OF

NEW YORK, Y.

SHOCK ABSORBER Application filed May 11, 1929. Serial No. 362,329.

The invention is an improvement upon shock absorbers such as disclosed in my 00- pending applications Serial Numbers 142,888, filed October 18th, 1926, and 247,405,filed January 17, 1928. It has for an object to present construction adapted to effect further improvement in functioning of such devices; to improve adaptability of-the invention to be produced by die casting operation; to present improved structure in the valve check device and manner of its mounting. Another purpose is to accomplish a novel improvement of means to conserve the liquid in the device. A further aim is to offer an improved means for returning to the reservoir liquid to escape around a shaft journalled in the case of the device.

A still further aim is to improve the structural elements of the device materially.

Additional objects, advantages and features of invention reside in the arrangement, construction and combination of parts as more particularly described in the following specification and the accompanying draw-- 55 ings, wherein V Figure 1 is an outer side elevation of an embodiment of the invention. 7

Figure 2 is a vertical cross section on the line 22 of Figure 1. V

Figure 3 is a top view of the device. Figure 4.- is a back view of the device with the back cover plate removed. I

Figure 5 is a sectional view on the line 5-5 of Figure 3. 1 Figure 6 is a horizontal sectional view on the line 66 of Figure 1; I

Figure 7 is a detail of one of the valve checks, or adjustable retarder.

Figure 8 is a detail section of the other valve check or adjustable retarder.

There is illustrated a spring compression and rebound check comprising a case 10 substantially circular, the back wall 11 and the peripheral wall 12 being die-cast integrally 4 in one piece with a completely finished piston chamber 13, in the lower part and an oil res ervoir 14 in the upper part, one operation being sufiicient for the production of the body,

of the case with all parts finished, except for 5a threading of certain apertures. The case has an open side formed with a flange 15 by which a. coverplate 16 is bolted thereto, and suitable cars 17 are formed on the case to enable its, ready mounting on a motor vehicle frame. The piston chamber is substantially sector,- shaped modified to suit the form of the piston 18.

The reservoir 14 is circular at its extreme upper part and cylindrical. A horizontal by-pass passage 21 is formed by a laterally drawn core in theupper part of the case body. Two ports 22 and 23 form communi-- cation laterally between this passage and the piston chamber at respective sides of the latter, equally spaced from a diameter of the case at right angles to the passage 21. Immediately inward of the port 22 at one side of the case the passage is enlarged as at 2 1. and aconical seat 25 formed. The enlarged part is continued to within a short distance from the ports 23 where a slight further en: largement of the passage is formed provid ing a seat 26 for a hardened tubular seat fitting or sleeve 27 which'is pressed thereinto and is ported in communication with the f port 23, the ports 22 and 23 and passage 21 forming a communication between opposite sides of the piston chamber, as may be understood. A ball 28 is freely movable in the part 24 of the passage, the ball being about two-thirds the diameter of this part of the passage for a purpose which will be explained. i

Thepassage 21 outwardly of the sleeve 27 is continued a short distance as a smooth cylindrical bore and then interiorly threaded to receive a bushing 29. The outer end of the passage through the sleeve is enlarged as at 30 and a steel washer 30- is disposed next the outer end of the sleeve, the opening through which is materially less in diameter than, the diameter of the enlargement of the outer end of thesleeve passage. In the bushing 29 there is threaded a screw 31 which pro jects inwardly of the bushing a distance and is formed with a plain cylindrical part '32 having a terminal lateral annular flange 32 which fits slidably and snugly in the enlargement 30 of the sleeve passage. Itslongitudinal' movement is thus limited outwardly tween the ball and the seat. This is a fool proof device, intended to prevent accidental or unwitting withdrawal of the pin to such extent that the ball may seat completely, which would cause breakage of the device or its connections if mounted on a vehicle and operatively connected with the axle and frame. The inner'end of the bushing 29 is formed with an annular vrshaped rib 34,

and between this end and the washer 30 there is a lead or other plastic metal gasket 35. Then the bushing is screwed forcibly home, the rib causes flowing of the metal laterally against the sides of the passage 21 and also inwardly against the smoothly finished cylindrical part 32 of the screw. There is a tendency for oil to leak around screws in such situations in devices of this character, and'my construction makes a leak proof device.

' At the opposite end of the passage 21 outward of the port 22 an enlargement 36 is provided of the same size as the part 30 of the passage through the sleeve 27, and a bushing 29, washers 30 and 35 and pin 33 such as described. If desired that the seat 25 shallbe of hardened material the construction for utilizing the sleeve 27 may be duplicated at this situation.

It should be noted that the passage 21 is cored in the casting close to the rear wall and'the reservoir extends downwardly "beside this cored part a distance. The upper part of the reservoir is circular, enabling itto be closed by a disc 37 having a pressed fit ina rabbet at the mouth of the reservoir. disc has an outwardly pressed apertured part interiorly threaded and receiving a closure screw 38. i

The piston is mounted in the device by means of a shaft 40 suitably secured in the piston, and having :a tenon 41 projecting at its inner end, while its outer end 42 is suitably extended from the case and adapted for mounting of an operating arm or the like. The cover 16 is formed with an axial recess 43 on its inner side, into which there is pressed a steel bearing collar 44 receiving snugly the tenon 41. .In the wall 11 there is also set coaxially a steel bearing sleeve 45 having a medial 'perimetral groove 46 on its lnner face from which leads an openlng having a duct 47 leading therefrom to the reservoir 14. The outer end of the sleeve is bev--' The elled on the inner side, the sleeve is exteriorly threaded, and a packing is confined against the shaft and end of the sleeve by means of a gland cap 48, as shown. Also screwed toward the case on the sleeve 45 there is a nut 49 bevelledon the inner side next its opening, and the opposed part of the case around the sleeve is also similarly grooved, a gasket 49 being confined therebetween to guard against leakage of liquid around the outer surface of the sleeve where it is set in the wall of the case. Suitable bosses 50 are formed exteriorly on the periphery of the case to accommodate the outer end portions of the passage 21, and the well or reservoir 14 includes also an extension of its wall upwardly from the body of the case.

An operating arm 51 is shown as fitted on the exposed end of the shaft, which arm may be connected with motor vehicle parts in any approved manner. The duct 47 is formed by inserting (before casting) in the properly formed aperture in the bearing sleeve a small pipe which remains permanently in place in the casting.

The'ports 22 and 23 are of considerable extent circumferentially of the" passages 21 and open laterally on the upper parts of pockets or recesses 52 forming continuations of the upper-part of the piston chamber 13, as well asopening downwardly into the piston chamber. Adjacent the level of the uppermost part of these pockets 52 oil outlet ducts 53 are formed in the body of the case, opening from the reservoir 14 on the front faceof the case adjacent the piston chamber extensions '52, where a slight enlargement is formed in each duct to accommodate a ball check valve 55 to "prevent movement of oil toward the reservoir. From the enlargements of these ducts lateral channels 56 are formed in the front face of the case body to the respective adjacent pockets 52 of the piston chamber. (See Figure 4). A port 5! is also formed from the reservoir into the passage 21, as shown in Figure 2. When the cover plate 16 is in place, the channels 56 serve as ducts between the piston chamber and continuations of the ducts 53.

In use,'the reservoir, piston chamber and passages being filled with oil, oscillations of the piston produced when the device is mounted on a vehicle and properly connected in accordance with familiar practice in such devices, will cause flow of oil back and forth through the passage 21-from one side of the chamber 13 to the other. This movement will be comparatively free in one direction as the ball 28 .will be held far from the seat fitting 27; but in the opposite direction movement will be opposed and restricted by reason of the ball being permitted to come much closer to the seat 25. The first movement is thatinvolved by compression of the spring of the vehicle, and the second is incident to return or the rebound movement. In the operation of the device, owing to the large clearance between the ball 28 and walls of the passage portion 2%, much oil will pass before the ball gains full momentum, and in fact it may never equal the speed of the passing oil.

In addition, owing to the distance the ball must move from one extreme of its path to the other, movement of the piston in either direction is not limited by the ball in initial stages of such movements, and it is only when such movements are continued to an extent representing extreme spring actions which require checking by the ball that it finally functions. On this account the vehicle body may float of the spring comparatively unchecked in response to minor inequalities and undulations of the roadway, and the checking action will occur only when more considerable inequalities are encountered.

The device may be adjusted quickly and to nicety of function by means of the screws 31, to adapt it to various loads, or to increase or decrease the sensitiveness of the shock absorber for any reasons. Oil which tends to escape by working outward around the shaft will be caught at the groove 46 and returned to the reservoir, by reason of the slightly vacuous condition produced therein by the functioning of the device. It will be understood that during the period when the ball 28 is moving in the part 24 of the passage 91, by operation of the piston, oil will be drawn out of this passage as rapidly as it enters, and consequently there is no tendency for oil to either enter or leave the reservoir. A the same time, however, oil is sucked out of the reservoir through the passages 5356 at one side of the device, and this will be principally replaced by oil entering the reservoir through the port 57 from the passage 21. But owing to the impedance at the point of entrance of the oil to the passage 21, the vacuous condition thus induced will be suflicient to insure return of oil from the groove 46.

It should be appreciated that the construction shown reduces to a minimum the tendency to air binding in the device. That is, if no means were provided for preventing accumulation of air in the piston chamber, a certain amount would accumulate there in time under some conditions, and the oil would be beaten into a frothy mass very elastic, and so easily compressible and expansible that the device would not function properly to;

check rebound and absorb shocks as intended.

By reason of the location of the ports 22 and 23 at the extreme uppermost part ofthe chamber 13, air is forced from the chamber into the passa e 21 promptly, and from the passage 21 it enters the reservoir through port rather freely with full action ing on the 57,and remains there above the liquid content.

I claim: l. A case for devices of the character described comprising a body having a semicircular piston chamber open on one side in the direction of its axis, formed in the case adjacent the truncated side of the piston chamber and extending symmetrically with respect to the chamber and its axis, said passage having enlarged outer parts, and a reservoir formed in the. body achacent the passage and open at theopenings from the piston chamber to the reservoir and from said passage to the reservoir are rectilinear and on axes parallel to that of the piston chamber.

In a device of the character described a case having formed therein a piston chamber and a bypass passage open on the ex terior of the case on at least one end, a valve movable in the passage, a port from the passage to the chamber, a seat outwardly of the port from the chamber and inwardly of the port from the open end of the passage, a screw member and closure in the open end of the passage, jected through the passage centrally of the seat, and means to limit withdrawal movement of the screw whereby. seating of the valve is permanently prevented and clearance from a predetermined minimum adjustable by said screw.

5. In a device of the character described a closure comprising a case having a by-pass passage therein having at least one end openexterior of the case, an enlargement and a shoulder in the inner limit of the a bypass passagesaid screw having a pin pro-' enlargement being formed at said opening, 7

a screw packing device being engaged in the enlargement, and having an annular V- shaped rib on its inner end, and a plastic metal-gasket confined between the rib and shoulder.

6. The structure of claim 5 in which a second screw device is engaged axially through the first formed with a plain cylindrical inner part, alined with the metal by the gasket will be crowded against the inner screw and the wall of the passage under pressure from the annular rib.

7. In a device of the character described, a case having a piston chamber'and a bypass passage having an open end on the periphery of the case, a port being formed from the passage to the chamber adjacent said end,

gasket, where-- a valve in the passage, a; seat between the port and the Valve concentric with the open end of the passage, an enlargement being formed in the passage outwardly of the port, a second enlargement outwardly of the first forming a shoulder, a washer set against the shoulder, a bushing screwed into the outer end of the passage having an inner terminal annular V-shaped rib, a plastic metal gasket confined between the rib and washer, an adjusting screw axially engaged through said bushing and having an inner smooth cylindrical portion whereby the gasket and circumscribing lateral flange will be compressed against both the adjusting screw and the wall of the enlargement of the passage, said flange being inwardly of said washer, whereby limiting of withdrawal of the screw iseffected, said screw having a port projected through said seat for the purpose described.

In testimony whereof I affix my signature.

ADNA F. BLANCHARD. 

